Monogame Shader Porting Issues

Question

Ok so I ported a game I have been working on over to Monogame, however I'm having a shader issue now that it's ported. It's an odd bug, since it works on my old XNA project and it also works the first time I use it in the new monogame project, but not after that unless I restart the game.

The shader is a very simple shader that looks at a greyscale image and, based on the grey, picks a color from the lookup texture. Basically I'm using this to randomize a sprite image for an enemy every time a new enemy is placed on the screen. It works for the first time an enemy is spawned, but doesn't work after that, just giving a completely transparent texture (not a null texture).

Also, I'm only targeting Windows Desktop for now, but I am planning to target Mac and Linux at some point.

Here is the shader code itself.

sampler input : register(s0);
Texture2D colorTable;
float seed; //calculate in program, pass to shader (between 0 and 1)

sampler colorTableSampler = 
sampler_state
{
    Texture = <colorTable>;
};

float4 PixelShaderFunction(float2 c: TEXCOORD0) : COLOR0
{
    //get current pixel of the texture (greyscale)
    float4 color = tex2D(input, c);
    //set the values to compare to.
    float hair = 139/255; float hairless = 140/255;
    float shirt = 181/255; float shirtless = 182/255;
    //var to hold new color
    float4 swap;
    //pixel coordinate for lookup
    float2 i;
    i.y = 1;

    //compare and swap
    if (color.r >= hair && color.r <= hairless)
    {
        i.x = ((0.5 + seed + 96)/128);
        swap = tex2D(colorTableSampler,i);
    }
    if (color.r >= shirt && color.r <= shirtless)
    {
        i.x = ((0.5 + seed + 64)/128);
        swap = tex2D(colorTableSampler,i);
    }
    if (color.r == 1)
    {
        i.x = ((0.5 + seed + 32)/128);
        swap = tex2D(colorTableSampler,i);
    }
    if (color.r == 0)
    {
        i.x = ((0.5 + seed)/128);
        swap = tex2D(colorTableSampler, i);
    }

    return swap;
}

technique ColorSwap
{
    pass Pass1
    {
        // TODO: set renderstates here.

        PixelShader = compile ps_2_0 PixelShaderFunction();
    }
}

And here is the function that creates the texture. I should also note that the texture generation works fine without the shader, I just get the greyscale base image.

public static Texture2D createEnemyTexture(GraphicsDevice gd, SpriteBatch sb)
        {
            //get a random number to pass into the shader.
            Random r = new Random();
            float seed = (float)r.Next(0, 32);
            //create the texture to copy color data into
            Texture2D enemyTex = new Texture2D(gd, CHARACTER_SIDE, CHARACTER_SIDE);
            //create a render target to draw a character to.
            RenderTarget2D rendTarget = new RenderTarget2D(gd, CHARACTER_SIDE, CHARACTER_SIDE,
                false, gd.PresentationParameters.BackBufferFormat, DepthFormat.None);
            gd.SetRenderTarget(rendTarget);
            //set background of new render target to transparent.
            //gd.Clear(Microsoft.Xna.Framework.Color.Black);
            //start drawing to the new render target
            sb.Begin(SpriteSortMode.Immediate, BlendState.Opaque,
                    SamplerState.PointClamp, DepthStencilState.None, RasterizerState.CullNone);
            //send the random value to the shader.
            Graphics.GlobalGfx.colorSwapEffect.Parameters["seed"].SetValue(seed);
            //send the palette texture to the shader.            
            Graphics.GlobalGfx.colorSwapEffect.Parameters["colorTable"].SetValue(Graphics.GlobalGfx.palette);
            //apply the effect
            Graphics.GlobalGfx.colorSwapEffect.CurrentTechnique.Passes[0].Apply();
            //draw the texture (now with color!)
            sb.Draw(enemyBase, new Microsoft.Xna.Framework.Vector2(0, 0), Microsoft.Xna.Framework.Color.White);
            //end drawing
            sb.End();
            //reset rendertarget
            gd.SetRenderTarget(null);
            //copy the drawn and colored enemy to a non-volitile texture (instead of render target)
            //create the color array the size of the texture.
            Color[] cs = new Color[CHARACTER_SIDE * CHARACTER_SIDE];
            //get all color data from the render target
            rendTarget.GetData<Color>(cs);
            //move the color data into the texture.
            enemyTex.SetData<Color>(cs);
            //return the finished texture.
            return enemyTex;
        }

And just in case, the code for loading in the shader:

BinaryReader Reader = new BinaryReader(File.Open(@"Content\\shaders\\test.mgfx", FileMode.Open));
colorSwapEffect = new Effect(gd, Reader.ReadBytes((int)Reader.BaseStream.Length));

If anyone has ideas to fix this, I'd really appreciate it, and just let me know if you need other info about the problem.

Answer 1

I am not sure why you have "at" (@) sign in front of the string, when you escaped backslash - unless you want to have \\ in your string, but it looks strange in the file path.

You have wrote in your code:

BinaryReader Reader = new BinaryReader(File.Open(@"Content\\shaders\\test.mgfx", FileMode.Open));

Unless you want \\ inside your string do

BinaryReader Reader = new BinaryReader(File.Open(@"Content\shaders\test.mgfx", FileMode.Open));

or

BinaryReader Reader = new BinaryReader(File.Open("Content\\shaders\\test.mgfx", FileMode.Open));

but do not use both.